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WCF Streaming: Upload/Download Files Over HTTP

, 9 Mar 2011 CPOL
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A sample for uploading/downloading large files from a browser to a WCF service via a web server.


Purpose of this article

I have tried to transfer large files over HTTP to/from WCF, but I have faced problems in that I was not able to upload files more than 45 KB in size. I have Googled over www, but I did not find any ready-to-use sample code/solution. Using the explanations over the www and MSDN, I have tried many configuration setting combinations and finally succeeded in transferring large files (I have tested up to 1GB on IE6).

I would like to share my experience so as to support efforts of others in this direction and to invite review comments from the developer community.


To transfer large files using “WCF service + HTTP”, we can use the following types of bindings:

  1. wsHttpBinding
  2. basicHttpBinding

In wsHttpBinding, we can set the transfermode attribute as Buffered, but there is a disadvantage in using this approach for large files, because it needs to put the entire file in memory before uploading/downloading, A large buffer is required on both the web client and the WCF service host. However, this approach is very useful for transferring small files, securely.

In basicHTTPBinding we can use the transfermode as Streamed so that the file can be transferred in the form of chunks. We have to ensure additional security mechanisms for transferring chunks. The security mechanisms are not explained in this posting.

Implementation: WCF Service

Create a new “WCF Service” project. Create a new service with the name TransferService. Now we will see an interface file “ITransferService” and a class file TransferService.cs. ITransferService should have two methods, one for upload and one for download.

WCF Service Sample Interface Code:
public interface ITransferService
    RemoteFileInfo DownloadFile(DownloadRequest request);
     void UploadFile(RemoteFileInfo request); 
public class DownloadRequest
    public string FileName;

public class RemoteFileInfo : IDisposable
    [MessageHeader(MustUnderstand = true)]
    public string FileName;

    [MessageHeader(MustUnderstand = true)]
    public long Length;

    [MessageBodyMember(Order = 1)]
    public System.IO.Stream FileByteStream;

    public void Dispose()
        if (FileByteStream != null)
            FileByteStream = null;
WCF Service Sample Interface Implementation Code:
public RemoteFileInfo DownloadFile(DownloadRequest request)
    RemoteFileInfo result = new RemoteFileInfo();
        string filePath = System.IO.Path.Combine(@"c:\Uploadfiles", request.FileName);
        System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath); 

        // check if exists
        if (!fileInfo.Exists)
            throw new System.IO.FileNotFoundException("File not found", 

        // open stream
        System.IO.FileStream stream = new System.IO.FileStream(filePath, 
                  System.IO.FileMode.Open, System.IO.FileAccess.Read);

            // return result 
            result.FileName = request.FileName;
            result.Length = fileInfo.Length;
            result.FileByteStream = stream;
        catch (Exception ex)

        return result; 
    public void UploadFile(RemoteFileInfo request)
        FileStream targetStream = null;
        Stream sourceStream =  request.FileByteStream;

        string uploadFolder = @"C:\upload\";
        string filePath = Path.Combine(uploadFolder, request.FileName);

        using (targetStream = new FileStream(filePath, FileMode.Create, 
                              FileAccess.Write, FileShare.None))
            //read from the input stream in 65000 byte chunks
            const int bufferLen = 65000;
            byte[] buffer = new byte[bufferLen];
            int count = 0;
            while ((count = sourceStream.Read(buffer, 0, bufferLen)) > 0)
                // save to output stream
                targetStream.Write(buffer, 0, count);


Settings of “Web.Config” in the WCF Service

The following settings are most important for transferring large data:

  • ReaderQuotas: We have to set the maximum sizes (this depends on our specific requirement). Here I have set to the maximum values where we can transfer data up to 2GB, as per MSDN/www documentation.
  • <binding name="TransferService"
           maxBufferSize="2147483647" transferMode="Streamed" >
    <readerQuotas maxDepth="2147483647" maxStringContentLength="2147483647" 
         maxArrayLength="2147483647" maxBytesPerRead="2147483647" 

    A word about my experiences here: I have used the above settings alone and received the error “400 bad request” from the WCF service on the browser.

    This error may occur due to many reasons: the reasons might be configuration mismatch between the web server and the WCF service, or an exception raised in the WCF service etc.

  • BindingConfiguration: This attribute is not available by default in the endpoint section. When I added this attribute, the “400 bad request” exception disappeared and the upload and download executed well.
  • <endpoint address="" binding="basicHttpBinding" 
              contract ="ITransferService">

    Along with the above settings, HttpRuntime settings should also be placed in the web.config file as below:

    <httpRuntime maxRequestLength="2097151" //Maxvalue
         executionTimeout="14400"   />  //can be configured as per the requirement.

Implementation: Web Server

Create a new “web site” project. Place a link button and a file upload control on the web page. Create one more button to upload the file. Add the reference of the WCF service in “Service References” with a suitable name, currently FileTransferServiceReference.

The following changes need to be done in web.config after adding the service reference:

<binding name="BasicHttpBinding_ITransferService" closeTimeout="04:01:00"
     openTimeout="04:01:00" receiveTimeout="04:10:00" sendTimeout="04:01:00"
     allowCookies="false" bypassProxyOnLocal="false" 
     maxBufferSize="2147483647" maxBufferPoolSize="2147483647" 
     messageEncoding="Text" textEncoding="utf-8" 
  <readerQuotas maxDepth="128" 
      maxStringContentLength="2147483647" maxArrayLength="2147483647"
      maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647" />
  <security mode="None">
      <transport clientCredentialType="None" 
              proxyCredentialType="None" realm="" />
      <message clientCredentialType="UserName" algorithmSuite="Default" />

Increase the values for the readerQuotas attribute and also increase the timeout settings.  

The code-behind of the page is the following:

protected void LinkButton1_Click(object sender, EventArgs e)
                    clientDownload = new TransferServiceClient();
        FileTransferServiceReference.DownloadRequest requestData = new DownloadRequest();

        FileTransferServiceReference.RemoteFileInfo fileInfo = new RemoteFileInfo();
        requestData.FileName = "";
        fileInfo = clientDownload.DownloadFile(requestData);

        Response.BufferOutput = false;   // to prevent buffering 
        byte[] buffer = new byte[6500];
        int bytesRead = 0;

        HttpContext.Current.Response.ContentType = "application/octet-stream";
                    "attachment; filename=" + requestData.FileName);

        bytesRead = fileInfo.FileByteStream.Read(buffer, 0, buffer.Length);

        while (bytesRead > 0)
            // Verify that the client is connected.
            if (Response.IsClientConnected)

                Response.OutputStream.Write(buffer, 0, bytesRead);
                // Flush the data to the HTML output.

                buffer = new byte[6500];
                bytesRead = fileInfo.FileByteStream.Read(buffer, 0, buffer.Length);
                bytesRead = -1;
    catch (Exception ex)
        // Trap the error, if any.
        System.Web.HttpContext.Current.Response.Write("Error : " + ex.Message);

protected void Button1_Click(object sender, EventArgs e)
    if (FileUpload1.HasFile)
        System.IO.FileInfo fileInfo = 
               new System.IO.FileInfo(FileUpload1.PostedFile.FileName);
        FileTransferServiceReference.ITransferService clientUpload = 
               new FileTransferServiceReference.TransferServiceClient();
               uploadRequestInfo = new RemoteFileInfo();

        using (System.IO.FileStream stream = 
               new System.IO.FileStream(FileUpload1.PostedFile.FileName, 
               System.IO.FileMode.Open, System.IO.FileAccess.Read))
            uploadRequestInfo.FileName = FileUpload1.FileName;
            uploadRequestInfo.Length = fileInfo.Length;
            uploadRequestInfo.FileByteStream = stream;

Now build both the IDE projects and execute the web server project. This still works only for less than 50KB! If you select a large file to be uploaded, you will see a blank webpage.

Now, you need to add one more attribute, MaxRequestLength, in the httpRuntime section in the system.web configuration file section, as below:

<httpRuntime maxRequestLength="2097150"/>

That is it! Now one can download and upload large files (I have tested up to ~1GB) from an IE6 browser over HTTP to a WCF service.


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


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Comments and Discussions

QuestionIE11- "The whatever.pdf download was interrupted Pinmemberkeslavi24-Sep-14 11:39 
BugMistake in your code [modified] PinmemberMember 1102032827-Aug-14 7:12 
GeneralRe: Mistake in your code PinmemberMember 1149170811-Mar-15 4:48 
QuestionFileInfo will not work in server PinmemberBig D13-Aug-14 5:47 
AnswerRe: FileInfo will not work in server PinmemberMember 1102032827-Aug-14 7:21 
QuestionUpload from Android and iOS PinmemberMember 1071530420-May-14 1:04 
QuestionThis isn't WCF, but hey concept is clear. thanks for sharing Pinmemberchetankumard2329-Apr-14 2:22 
AnswerRe: This isn't WCF, but hey concept is clear. thanks for sharing PinmemberMember 111826663-Mar-15 3:58 
GeneralMy vote of 5 PinmemberMohammed Irfan27-Apr-14 19:37 
GeneralMy vote of 1 PinmemberMohammed Irfan25-Apr-14 3:32 
Question(400) Bad Request Error PinmemberMember 445279122-Dec-13 22:40 
Questionbad request 400 error while uploading file larger than 64k PinmemberKalpesh Bhadra19-Dec-13 20:38 
QuestionIt's Possible using in The Wndows Phone 8?? [modified] PinmemberMember 96716403-Dec-13 5:01 
GeneralRe: It's Possible using in The Wndows Phone 8?? PinmemberWamuti29-Jan-14 9:41 
BugHttp 400 Error : There might be a typing error in the address. Pinmemberprasad135926-Oct-13 22:41 
QuestionWhat about Upload with a boolean return? Pinmembersoflp-pt25-Sep-13 13:39 
AnswerRe: What about Upload with a boolean return? PinmemberMember 1071530425-Jun-14 20:24 
GeneralRe: What about Upload with a boolean return? PinmemberMember 1149170820-Mar-15 5:51 
QuestionThe compiler failed with error code -1073741502 Pinmembershauncollege23-Sep-13 4:50 
GeneralMy vote of 5 PinmemberJaikrishan6-Aug-13 21:38 
Questionfailed to allocate a managed memory buffer of bytes. the amount of available memory may be low Pinmemberv.narasa11-Jul-13 0:29 
QuestionCannot work alongside data contracts PinmemberRakesh Vasu3-Jul-13 10:41 
QuestionCannot run the example code Pinmembergiropau27-Jun-13 1:32 
QuestionDoes this work with a Java Client? Pinmemberniceguyorl12-Jun-13 9:22 
QuestionAborting PinmemberKolompas Lajos27-May-13 22:36 
QuestionClients under proxy where there is http 1.0 protocol support only PinmemberMosfiqur Rahman3-Mar-13 0:19 
GeneralGreat Example PinmemberVasistan Shakkaravarthi26-Feb-13 4:38 
QuestionHow do you then call UploadFile from javascript? Pinmemberdgrassel15-Feb-13 11:56 
Preferably using XMLHttpRequest and JSON?
GeneralMy vote of 5 Pinmemberabellix16-Jan-13 13:18 
QuestionThis option is not supported in the WCF test client because it uses type... PinmemberR.SIVAA4-Dec-12 2:54 
AnswerRe: This option is not supported in the WCF test client because it uses type... Pinmemberabellix16-Jan-13 13:17 
GeneralMy vote of 5 PinmemberDaoNhan15-Oct-12 16:54 
QuestionGetting a "(415) Unsupported Media Type.HTTP GET" error Pinmemberwinny8713-Oct-12 4:37 
AnswerRe: Getting a "(415) Unsupported Media Type.HTTP GET" error Pinmemberv.narasa9-Jul-13 5:30 
AnswerRe: Getting a "(415) Unsupported Media Type.HTTP GET" error Pinmemberv.narasa11-Jul-13 0:23 
QuestionAccess is denied question PinmemberMember 836848113-Sep-12 4:49 
AnswerRe: Access is denied question Pinmemberchirag zadafia13-Sep-12 21:50 
QuestionUnable to cast object of type 'System.String' to type 'System.IO.Stream'. Pinmemberchirag zadafia6-Sep-12 4:19 
QuestionHi Pinmemberapandey214-Sep-12 4:10 
GeneralMy vote of 5 Pinmemberseankearon25-Jul-12 22:08 
Questionwhen the client close the connection with WCF service? Pinmemberinformes empresas27-Jun-12 3:00 
QuestionThank you PinmemberRajalingam2219-Jun-12 20:18 
QuestionMay contact me please? Pinmemberstranet4-Jun-12 6:48 
AnswerRe: May contact me please? Pinmemberblankkk19-Jun-12 3:40 
QuestionHow would this be done, using TCP? PinmemberRod Falanga23-May-12 8:18 
GeneralMy vote of 5 Pinmemberrjayaram0117-Apr-12 16:47 
QuestionExcelent work Pinmemberpsycker29-Mar-12 12:11 
QuestionSecurity Pinmemberblankkk28-Mar-12 1:14 
QuestionProgress bar PinmemberMember 217505113-Mar-12 7:10 
SuggestionSome Clarifications Pinmembercdamour11-Mar-12 19:56 

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